Means for producing a drawable staple sliver



H. o. HESS 2,795,010

mus FOR PRODUCING A DRAWABLE STAPLE SLIVER I June 11, 1957 Filed April9. 1953 INVEVNTOR. HEINRICH Orro Hess.

WLL M ATTUKNEK United MEANS FOR PRODUCING A DRAWABLE STAPLE SLIVERApplication April 9, 1953, Seriai No. 347,728 Claims priority,application Switzerland April 10, 1952 5 Claims. (Cl. 19-556) Variousmethods and means have been proposed to transform a strand consistingsubstantially of endless filaments into a drawable staple fibre strand.

Because of their reliability and economical operation, severingdevicesof the crimping or squeezing type have been found particularly suitable.

Many different devices have been used for restoring parallelism of thestaple fibres which was disturbed by the cutting operation and forrefinement of the mass of staple fibres .in subsequent operating stages.All, these devices, however, did not fully answer the requirements andaccount for the particularities inherent to the use of severing elementsof the squeezing type.

Many synthetic fibres are welded together by the great specific pressureexerted by the edges of the cutters. The so produced tufts causeconsiderable difficulties during subsequent operations particularly atdrawing operations. It is of primary importance to sever the particles,called fish-food, which hold the fibres forming a tuft together and toremove the particles from the layer of fibres. It has been proposed toarrange pairs of cooperating deeply stardiuted rollers between which theroving 8 Patent F coming from the cutter is pulled. The result, however,

difiiculties experienced with conventional arrangements by positivelyguiding the roving continuously produced by squeezing the filaments andsubjecting the guided rovingalternately to a multistage forwardly andrearwardly acting combing and simultaneously to a drawing action andsubsequently condensing the sliver to form a coherent strand. Theinvention also provides an apparatus for performing the method whichapparatus comprises a conventional severing device of the squeezing typefollowed by a combing and drawing device which comprises a plurality ofpairs of clamping rollers which are spaced according to the staplelength; the apparatus also comprises pairs of needle rollers interposedbetween the clamping rollers, the speed of the'former at the needlesbeing greater than that of the feed rollers but less than that of thedelivery rollers, and means for condensing the staple fibre layer comingfrom the combing and drawing device and compressing the layer to form acompact strand.

The novel features which I consider characteristic of my invention areset forth with particularity in the appended claims. The inventionitself however and additional objects and advantages thereof will bestbe understood from the following description of embodiments thereof whenread in connection with the accompanying drawing in which Fig. 1 is adiagrammatic layout of the system according to the invention;

Fig. 2 illustrates a cut filament strand;

Patented June 11, 1957 I Fig. 3 is a large scale illustration of twodifferent tufts of which the strand shown in Fig. 2 is composed;

Fig. 4 is a diagrammatic illustration of a modified drawing andcombingframe;

Fig. 5 shows a pair of needle rollers;

Fig. 6 is a diagrammatic side view of a condensing device;

Fig. 7 is a sectional viewof the device shown in Fig. 6, i

no sharp edges, the edges being flattened to a width of 0.3 to 0.5 mm.which is permissible because of the high specific pressure at which theedges are pressed against the surface of the counterroll, the dull edgesreducing wear. The knives of the cutting roll may be arranged in singleor multi-thread fashion, the circumferential spacing of the knivescorresponding to the desired staple length. An elastic filling 4 ispreferably provided between the knives to securely clamp the filamentlayer during the cutting operation and to prevent lateral displacementof the individual fibres. Other suitable cutters operating on the samerinciple may be used instead of the one described supra. A pair ofclamping rolls 5 is placed proximately to the cutting device which rollsare followed by further pairs of clamping rolls 6, 7, and 8 at distancescorresponding approximately to the length of the cut staple. Pairs ofneedle rolls 9, 10, and 11 are individually arranged between the pairsof clamping rolls. The needles 12 of the rolls are arranged in rows, theneedles of one roll of a pair extending between the needles of the otherroll of the same pair. Spacer rings 30 and 31 arranged at the ends ofthe needle rolls prevent contact between the needles of one needle rollwith the surface of the opposed needle roll, see also Fig. 5. It hasbeen found of advantage to place the needle rolls in each combing fieldimmediately ahead of the delivery rolls of the combing field. The numberof pairs of clamping and needle rolls may be greater or smaller than thenumber shown in Fig. 1, without departing from the scope of the presentinvention. The needle rolls are positively driven by conventional means,not shown. Other necessary drive means as well as the means for pressingthe rollers of each pair against each other are all of a conventionalnature and are therefore not illustrated.

A condenser 14 follows the drawing and combing device for condensing thespread out, cut, and combed filament layer 15 to form a roving ofcircular cross section. The latter is received in a compression devicecomprising a pair of feed rollers 16 and a compression chamber 17.

The filament layer 18, which is to be processed and which has previouslybeen tensioned and spread to the desired width, is passed betweencalender rolls 19 to equalize the thickness of the layer before enteringthe cutter 1, 3. By squeezing the layer in the cutter at distancescorresponding to the desired staple length, an incoherent staple fibrelayer 20 is produced as shown in Fig. 2. As has been mentioned before,many synthetic fibres have a tendency to be welded together to formfibre tufts 21 (Fig. 3) due to the high pressure at which they arecompressed in the cutter, the fibres of each tuft having a commonparticle 22 known as fish-food. The

ends of a bundle of fibres are frequently welded together in groups 22.

The fibre layer 20 composed of fibre packages or tufts of the type shownin Fig. 3 are gripped by the clamping rollers 5 whose distance from thecutter 1,. 3 is smaller than the staple length and whose drawing speedcorresponds to the delivery speed ofthe. cutter. The rollers 5.

transport the roving toward the needle rolls 9.. The rolls of the nextfollowing pair of clamping rolls 6 rotate faster than the clamping rolls5. The circumferential speed of. the needles 12 of the. needle rolls 9is between the speed of the neighboring clamping rolls 5 and 6. Thisproduces thorough combing of the fibre packages 21 held by the feedrolls 5 from both sides and beginning at the forward ends of thepackages. The welded fibres are separated from the compression particles22 and placed in parallel. relation, the particles 22 being dropped. Assoon as the fibres have left the nip of the feed rollers 5, they aregripped by the delivery rolls 6 and pulled away at aspeed which isgreater than the circumferential speed of the needle rolls 9. A combingeffect is thereby pro duced also at the rear end of the fibres.

The above described process is repeated in the following combing fieldswhereby the cut staple fibre layer is positively guided, incontradistinction to conventional gelling devices, and alternatelysubjected to a forwardly and rearwardly effective combing action so thatthe fibre mass is refined in accordance with the draft in the individualcombing fields. The .result is a hank which is clean and homogeneous,and in which the individual fibres are completely. separated andparallel. The removal of the squeezing residues or nips 22 eliminatesformation of clusters in subsequent operations.

The number of needles 12 may be increased in the second andthird combingfield to increase the combing efiect. Groups of two or more adjacentrows of needles may be arranged on the needle rollers, for example asshown in Fig. 4.

The circumferential speed of the needle rollers is adjusted closer tothat of the feed rollers or of the delivery rollers, according to theresult desired. It has been found advantageous to adjust the speed ofthe needle rollers in the first combing field similar to that of Thefibre layer 15 leaving the combing and drawing device is incoherent andis fed into a device 14 which transforms the layer into a strand ofcircular cross section. The latter is pulled by a pair of rollers 16into a compression chamber 17 where the strand is condensed orcompressed into a staple fibre strand 23 which is suitable for transportand further processing. The finished strand may be packed into cans inthe conventional manner.

Fig. 4 illustrates a modifiedcombing and drawing device. .An angularguide plate is provided between. the feed rollers 24 of the firstcombing field and the needle rollers 27. The guide plate 25 has aportion 26 proximal to the feed rollersand positioned substantiallyradially of i the lower needle'roller 27. The guide plate has a secondportion 28 which is curved and shields the needles 29 of the lowerroller 27 on a part of the circumference of the roller against the upperneedleroller 27. In order to prevent contact of the needles of the twoneedle rollers 27 with the guide plate 25, the latter rests on spacerrings 30 and 31, whose outer diameters are greater than the diameters ofthe circles on which'the points of the needles are located. Effectiveinterpositioning of the needle rows, in spite of the guide plate portion28, is assured by arranging the spacer rings 30 and. 31 in axiallystaggeredrelation, as shown in Fig. 5. A similar 4. guide plate 32 maybe provided also in the subsequent combing field, which guides the fibrelayer in the described manner into the nip of the pair of rollers 33which are provided with groups of three adjacent needle rows. The combson the pair of rollers 33 are preferably made finer than the combs onthepair of rollers 27.

The staple fibre layer coming from the feed rollers 24 is diverted fromits horizontal path and directed in substantially radial directiontoward the lower needle roller 27, in contradistinction to thearrangement shown in Fig. I in which the fibres are directed into thenip and tangentially of the needle rolls. Combing of the forward ends ofthe individual tufts 21 is thereby improved. The combing effect isfurther intensified by the portion 28,0f the guide plate 25 which causescomplete penetration of the tufts by the needles 29 of the lower roll27.

Instead of the condenser 14 shownin Fig. 1 for concentrating the combedfibre layer 15, a device according to Figs. 6 and 7 is preferablyprovided, which comprises a forwardly pointed feed table or platform 34whose sides are formed by endless belts 35 and 36 which are looped aboutvertical guide rolls 37, 38 and 39, respectively, and move in'thedirection of the arrows shown in Figs. 6 and 7. The feed table isdownwardly inclined between the guide rolls 37, 39 and 38, 40 -(Fig. 7)so that the direction of movement of the fibres on the table deviatesfrom the direction of movement of the lateral belts 35 and 36. Thevelocity component of the latter in the direction of movement of thefibre material corresponds substantially to the speed of the feed rollerpair 41 and to that of the feed rolls 42 of the compressing chamber 43.

Sliding of the fibre layer fed by the rolls 41 onto. the feed table 34toward the roller pair 42 is assisted by the decline of the table. Thelayer is simultaneously compressed from the sides by the moving belts 35and 36. Due to the relative position of the feed table and the lateralfeed belts, the lateral portions of the web are raised relatively to thecenter portion of the fibrous web which assists rolling-in of the layerfrom both sides and rounding of the strand without tearing. Byincreasing or decreasing the speed of the belts a relative motionbetween the marginal portions of the fibre layer and the belts can beproduced, if desired. Laterally projecting fibres can thereby besmoothed back into the layer.

The angle formed by the belts 35 and 36 is preferably to more obtuseangles cause too great relative speeds of the belts, whereas too acuteangles impede sliding of the fibres ,due to the greater length of thefeed table.

Fig. 8 shows a knife roller 44 one half of which. is provided with kniferidges arranged in left-hand threaded fashion and the other half ofwhich is provided with knife ridges in right-hand threaded fashion. Thisproduces a symmetric pattern of the cuts of the fibre layer which isindicated by dotted lines in Fig. 6 and which assist rolling the layerinto a strand.

While I have shown and described specific embodiments of my invention,it will be apparent to those skilled in the art that various changes,modifications, substitutions, additions and omissions may be madetherein Without departing from the spirit and scope of my invention asset forth in the appended claims.

What is claimed is:

1. An apparatus for transforming a layer of endless filaments into adraftab le staple fibre strand comprising, in combination, a severingdevice of the blunt cutting type, a pair of feed rollers receiving thesevered filaments from said severing device, a pair of delivery rollersreceiving the staple fibres from said feed rollers, the distance betweensaid feed rollers and said delivery rollers slightly exceeding thestaple length, a pair of superposed needle rollers interposed betweensaid pairs of feed rollers and said pairs of delivery rollers forcombing the staple fibres, the circtunferential speed of the needles ofsaid needle rollers being greater thanthat of said feed rollers andsmaller than that of said delivery rollers, a condensing devicereceiving the staple fibres from said delivery rollers, and acompressing device receiving the staple fibres from said condensingdevice for forming a coherent staple fibre strand, each of said needlerollers being provided with rows of needles, the rows of needles of oneneedle roller of the pair being consecutively interposed between therows of needles of the other roller of the pair upon rotation of therollers, said needle rollers being provided with coaxial spacer rings toprevent contact of the points of the needles of one needle roller withthe other needle roller.

2. An apparatus according to claim 1, the radial extension of saidspacer rings being greater than that of the needles, the rings of theneedle roller of one pair being axially staggered with respect to thespacer rings of the other needle roller of the pair.

3. An apparatus for transforming a layer of endless filaments into adraftable staple fibre strand comprising, in combination, a severingdevice of the blunt cutting type, a pair of feed rollers receiving thesevered filaments from said severing device, a pair of delivery rollersreceiving the fibre material from said feed rollers, a pair ofsuperposed needle rollers interposed between said feed rollers and saiddelivery rollers for combing the fibre material, guide means for thefibre material interposed between said feed rollers and said needlerollers and comprising a first guide portion deflecting the fibrematerial from a straight line between the nips of said feed rollers andof said needle rollers, said guide means comprising a second guideportion covering one of said needle rollers on a portion of itscircumference, and a condensing and compressing device receiving thestaple fibres from said delivery rollers and forming a coherent staplefibre strand.

4. An apparatus as defined in claim 3 comprising spacer rings on each ofsaid needle rollers to prevent contact of the points of the needles ofone needle roller with the other needle roller, said second guideportion having lateral portions adjacent to said spacer rings.

5. An apparatus for transforming a tow of endless fil'aments into adraftable staple fibre strand comprising, in combination, a severingdevice of the blunt cutting type, a pair of feed rollers receiving thesevered filaments from said severing device, a pair of delivery rollersreceiving the fibre material from said feed rollers and having a greatersurface speed tlran that of the feed rollers, 21 pair of superposed pinrollers interposed between said pair of feed rollers and said pair ofdelivery rollers, the circumferential speed of the pins on said pinrollers being greater than that of said feed rollers and smaller thanthat of said delivery rollers, and condensing means disposed downstreamof said delivery rollers with respect to the movement of the filaments,said condensing means including two vertical horizontally movingconverging endless belts, and a pair of superposed horizontal rollersdisposed adjacent to said belts where said belts are closest together,the nip of said horizontal rollers being lower than the nip of saiddelivery rollers.

References Cited in the file of this patent UNITED STATES PATENTS2,142,475 Lohmann Ian. 3, 1939 2,249,083 Kern July 15, 1941 2,293,712Campbell Aug. 25, 1942 2,43 8,469 Wilkie Mar. 23, 1948 2,492,306 MackieDec. 27, 1949 FOREIGN PATENTS 1,840 Great Britain of 1860 518,995 GreatBritain Mar. 13, 1940 895,435 France Jan. 24, 1945

